


Darling, It's Better Down Where It's Wetter

by KelinciHutan



Category: Supernatural
Genre: Alternate Universe - Reader Insert, Gen, Mermaids, casefic
Language: English
Status: Completed
Published: 2014-09-03
Updated: 2014-09-03
Packaged: 2018-02-16 00:30:50
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,498
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2249199
Author URL: https://archiveofourown.org/users/KelinciHutan/pseuds/KelinciHutan
Summary: <blockquote class="userstuff">
              <p>So, you were starting to think that going after that witch might not have been your best plan ever.  At least, not alone.  Because now you had a fish tail.  That damned witch had turned you into a mermaid.</p>
            </blockquote>





	Darling, It's Better Down Where It's Wetter

**Author's Note:**

> I wrote this in response to an “imagine” from the supernaturalimagine tumblr. This is, in essence, a short prompt or idea submitted by someone about Supernatural. They range from adventurous to romantic, but most involve a reader-insert. This is one such imagine, the conceit of which is that the reader is part of the SPN gang. The imagine that prompted this can be found [here](http://supernaturalimagine.tumblr.com/post/96412757927/anonymous).

So, you were starting to think that going after that witch might not have been your best plan ever. At least, not alone.

Not that you hadn't had motivation. A string of missing girls from her area was powerfully motivating. Nobody deserved to be kidnapped, obviously, but it felt worse when it was kids. Dean and Sam had wanted to wait, but you hadn't been able to keep still once you knew where she lived. So you'd headed out after her on your own.

Which, okay, mistake. You were 100% sure about that now.

You had come to this brilliant conclusion right about when the witch threw that potion at you, and you'd poofed out of her house—which had been stunningly nice and why did the evil people get all the good stuff—into one of the bathtubs of the bunker. In fact, this was the one on the hall you shared with Dean and Sam. You'd recognize that little stain on the inside of the curtain anywhere.

You struggled to stay standing, because for some reason that was incredibly painful, then flopped down hard into the ceramic tub. This didn't seem right. Something was wrong. Surely your legs weren't broken. You looked down.

You didn't have legs anymore.

You had once thought loosing a limb and seeing the space where it used to be would be pretty traumatic. And you still figured that it would be. But you could now say for a cold fact that having two limbs replaced by something else entirely was its own brand of freaky.

You had a fish tail. That damned witch had turned you into a mermaid.

At least you could still breathe air.

Okay. A mermaid. You could fix that. Or Cas could. But either way, this was fixable. All you had to do was get to the library and do some research. You moved hands that suddenly had webbing between the fingers, and started to get to your feet. You had actually levered yourself a good way up with your arms (which was hard with webbing between your hands limiting how you could move them) before you started putting any weight onto your legs. Which were no longer there, resulting in you crashing back to the tub, with a thud, and a lot more pain.

Tears actually sprang to your eyes at this, and for a moment you considered giving in, hiding in this stupid tub with the curtain closed, and just crying. It wasn't like you didn't have good reason. Admittedly things were getting better, but after last year… Sam narrowly escaping death, only to turn out to be possessed by an angel. Because of _Dean_. And with Cas gone so much of the time, that had left you and Kevin to navigate the bunker between the two Winchesters. Both of whom occasionally took their frustrations out on the two of you. You, admittedly, didn't have a whole lot in common with Kevin, but sheer boredom with the bunker and frustration with the brothers had the two of you bonding, forging a real friendship, and eventually running a few local salt-and-burns on the side. Dean and Sam's heads had been too far up their asses to notice ghosts in their own town, so the two of you had handled it. It had needed doing.

Then Kevin had been murdered. And then Cas had gone back to being an angel but something was wrong with his grace. The Metatron had _killed_ Dean. _Who had turned into a demon._

Things had just gotten, kinda sorta, back on track. Dean was human again, the Impala was clean, Cas wasn't dying of poisoned grace. And now you were a mermaid. And something about the way the bones (cartilage?) in your brand new tail connected to your spine meant that you felt the pain from hitting the tub, twice, really hard, all the way down to the tips of your brand new fins. So, on top of everything else, you were in a lot of pain.

So, yeah. Crying for a few years or so seemed like a really attractive option right now. In fact, a couple tears actually managed to escape before you sniffed and pulled yourself together. They fell from your face and hit your tail.

Where the tears fell, the pain lessened. You gasped in surprise and instantly turned on the faucet.

Going for the hot first was a mistake. What had been pleasantly warm to a human was scaldingly hot to a mermaid, apparently. You whimpered in pain as you shut off the hot tap and turned the cold one.

Deliciously warm-feeling water started filling up the tub and you sighed in pleasure. Everywhere the water touched, the pain began to subside. It felt so, incredibly, good.

You filled the tub to cover your tail completely, and then began to take inventory. The witch's transformation had done something to your phone and weapons. You were sitting in this tub with some kind of backless leather jerkin covering the front of your torso and tied in the back at your neck, and around the bottom of your shoulderblades. But that was it for clothes. No tools, no weapons, no communication.

Okay, so obviously your first step was to get out of the bathroom.

You were about to start hauling yourself up from the tub (by your arms, since you had learned the whole you-don't-have-legs-right-now lesson pretty painfully), when the door to the bathroom opened.

Since the curtain was closed, you couldn't see who had just come in. You opened your mouth to call out and then realized you were about to have to explain your newly aquatic status. And you totally blanked on what to say, because _how do you explain something like that?_

A fully naked Sam confidently pulled the curtain back.

“Augh!” Sam yelled stumbling backwards.

“Augh!” you echoed, turning your face towards the wall.

To be entirely clear, naked Sam Winchester is the opposite of an unpleasant sight. But there were conventions about looking at people naked that included things like permission, so you kept your eyes fixed firmly on the boring tile wall.

“Are you…? How…? Why is there a mermaid in our shower?” Sam yelled. You heard some fabric rumpling that probably meant Sam was getting dressed as fast as possible.

“About that,” you began.

“Wait.” Sam took two steps, and was suddenly beside the tub. “Look at me,” he commanded sternly.

You turned your head. Sam was clothed, thankfully, in jeans and a tee shirt.

Sam gasped out your name. “What the hell are you d—? How did yo—? _**Why are you a mermaid?**_ ”

“Erm…remember that witch we were looking at tracking?” you said sheepishly.

Sam blinked.

“She got me.”

Sam's lips started twitching.

“This isn't funny, you massive jerk!” you yelled.

“Sam,” said Dean's voice—the worst voice in the world right now, “if this is the treatment you get from girls in the shower…whoa.” The entrance of Dean's voice had been shortly followed by the entrance of Dean, who was now gazing down at you, mermaid tail and all, in the bathtub, with water up to your waist. “So, I'm guessing there's a story here.”

“Apparently, she tried to hunt our witch,” Sam told Dean.

Now Dean's lips started twitching.

“I hate you both,” you snarled.

“Now, don't be like that, oh jewel of the waters,” Dean said.

You flung the nearest bottle of shampoo at his head, which he ducked. The shampoo hit the far wall, and exploded, sending purple goo cascading down the tiles.

Apparently this was the last straw and the two Winchester brothers dissolved into gales of laughter. And after a moment, you gave in and joined them. It had been _so long_ since either of them had been happy and laughing. Even if it was at your expense, it was good to see them smile.

Getting you to the library proved to be a trickier operation that you would have thought. Fish tails were, apparently, slimy and slippery, and thus tough to get a grip on. Sam had initially tried to slide an arm under your back and one under the tail, but despite your efforts to keep it firm, your tail kept sliding off of his arm. Then they'd tried having you sling one arm across Sam's shoulders, and one over Dean's, but your webbed hands were bad for gripping anything, and all three of you ended up in pain from slaming some joint or other into the doorframe on the way out of the bathroom.

Finally, Dean had muttered something incredibly rude and then hauled you over his shoulder in a fireman's carry and set off towards the library at a confident stride.

Again, just for clarity, being carried around by Dean Winchester is absolutely not a bad thing. But not even being able to walk was humiliating, and you kept having to duck all the doorframes, something you were ordinarily too short to need to worry about.

But finally you and Dean were ensconsed in the massive library in the bunker (Sam having gone off to actually take his shower), poring over every dusty old tome you could get to (which was, for you, mostly on the lower shelves). And you were starting to be very annoyed with this leather jerkin/halter top thing that had no support at all. Your “girls” were very unhappy campers, and you were seriously considering slapping Dean in the face the next time his eyes roamed over you as you levered yourself around on the floor. Or tried to figure out how to handle books with hands that were suddenly better suited to swimming.

Still, he was calling out Castiel's name every few minutes, and he wasn't really leering at you so much as just a little distracted, so you decided to let it slide. Eventually—finally—there was the welcome sound of invisible wings and Castiel stood beside Dean.

“What?” was the first word out of the angelic newcomer's mouth, dripping with annoyance.

“We've got a problem,” Dean said.

“Good. As much as you've been calling me, you'd better,” Cas answered. “What is it?”

“Down here,” you said, waving when Cas' eyes landed on you.

Castiel took you in. Webbed hands struggling with a dusty tome, mermaid tail that was shaped like a cross between a shark's and a sea snake's lower halves, now that you thought about it. He stared for a full ten seconds and finally said something.

“Have you always been a naiad?”

Which, okay, was not what you had expected him to say. “I have never been a Greek water spirit,” you replied.

“You are, obviously, a naiad now. But naiads are capable of shifting form, to appear fully human. When they do so, they're indistinguishable from actual humans, even to angels,” Cas explained.

“Wait, you mean I can get my legs back?” You were about to get excited.

Cas knelt beside you and put a gentle hand to your cheek. “Oh. Magic. No, you're locked into this form.”

“Damn,” you sighed.

“And you can't, I dunno, heal her or something?” Dean asked.

Cas rolled his eyes and put two fingers to the center of your forehad. A wave of sensation swept through you, and all the residual pain from your falls vanished.

“She's now the healthiest naiad in the world,” Cas told Dean irritably.

You smirked. Cas's restoration to healthy, not-dying-or-losing-grace angel status had not rid him of his snarky side.

“So how do we fix me?” you asked.

“Only a naiad can cast a spell to turn you into a naiad. To change you back, we have to find the naiad that did this and get her to reverse the spell,” Castiel said.

“I don't think she's going to be open to persuasive argument,” you muttered. “She kidnaps little girls for fun.”

Cas shrugged. “Killing her will also reverse her magic.”

“Great. There's gotta be something in here about how to gank a night lad,” Dean said, striding for the index.

You exchanged a glance with Cas, both of you deciding that Dean probably knew perfectly well how to spell “naiad” and was just running his I'm-a-dumb-high-school-drop-out rig again. And sure enough, all the books he brought back to the research table were 100% on point.

Castiel carried you to a seat at the table (much more gracefully than Sam or Dean had carried you), and you all settled in to researching stories about naiads, their origins, and on and on. Some of them were even in Greek, which you and Dean happily handed to Cas, or Sam when he returned from his shower.

There just wasn't a lot about _killing_ naiads anywhere.

It was actually an eye-straining hour later when you finally said, “Found it!” Sam looked up from the pages of _Nymphs And Their Ways_ , and Dean and Cas stopped squabbling over _Dreadful Denizens Of The Deep_.

You had been slogging through a Men Of Letters notebook titled _Water Monsters_ (that was a lot thicker than you wished it was) before finally hitting the “Naiads” entry.

“'Naiads are capable of magic, but can be hurt or killed in the same ways as a human. No spells or artifacts are required,'” you read out.

“All right,” Dean said, snapping _Dreadful Denizens Of The Deep_ shut. “Sam, grab your gear. Let's go.”

He and Sam stood, before you said, “Ah, guys?”

Sam turned back, looking at you in confusion. “We've been _carrying_ you around the bunker. Exactly how much help could you be on this one?”

“Considering our magic bitch has a massive lake that her house actually hangs over, a lot,” you returned. “She's not just a witch, she's a naiad. And she can teleport. If she gets into the water, you two can't follow her. I can.”

The two brothers exchanged a glance, before Dean said, “Fine. You're our back-up. If she goes for the lake, she's all yours.”

So you got loaded into the back seat of the Impala along with Cas. And if Cas seemed oddly fascinated with stroking your mermaid's tail, you were hardly going to tell him to stop. Honestly, a girl could get used to all this attention from the boys. Dean and Sam slid into the front, and you were off to see the witch.

It was about a four hour drive from the bunker to the naiad's lake, and you had been telling the truth when you said that the lake was massive. Back when you were a kid, you'd had a picture book of the story _Swan Lake_. And the pictures of the lake, though beautiful, had been your least favorite. Massive, black, deep, and cold.

This lake looked like the one from the book. Like someone had taken a thunderstorm and trapped it in the water. There was only one house on the shore, despite this being a perfect picturesque setting for one of those stupid, cookie-cutter, lake-front, rich-people housing developments that seemed to be utterly inescapable these days. Maybe the naiad had done some kind of spell? In which case, it seemed almost sad to mess it up.

Heh. What were you thinking? You wanted your legs back. That merwitch was going down.

Dean parked the car a pretty far way off from the house. You all got out, with you sitting on Cas' shoulders, tail wrapped firmly around him in a way that was surprisingly comfortable and stable. You were starting to get the hang of your new muscles. Sliding a hand over your tail, you could see why Cas had been so fascinated with touching it. Beneath your skin, you felt strong sinews curving into unfamiliar structures. You had powerful muscles. You'd be formidable in the water.

The four of you reviewed the plan one more time, while you all grabbed some weapons. Since you'd be in the water, if you were anywhere, you strapped a harpoon gun to your back, and slid a quiver of extra harpoons onto your hip.

Dean and Sam would mount a frontal assault on the house while you and Cas would wait, invisible, on the porch hanging out over the lake. All four of you would be wearing hex bags to repel magic. And hopefully, Dean and Sam would be able to take out the witch without you needing to go for a swim.

You and Cas took up your positions on the porch and waited.

It wasn't long before you heard Sam kick in the front door, and then a series of shouts emerged from the front room. But it sounded like more than one person.

You leaned over to peer through the massive glass doors that led into the house and saw the witch and two little girls all running towards you.

“They're coming, Cas!” you whispered.

“They?” he said from below you.

The glass door slid open so fast it shattered. You barely contained a shriek as you were showered with little shards. The witch was first onto the porch, diving into the water, transforming as she did. The two girls were next, both crying, and both moving like they were being jerked along by invisible strings. They transformed too, as they were yanked off the the deck.

Sam and Dean were pounding along behind, guns pointed downwards, to avoid hitting the girls. Apparently they'd been unable to get a clean shot at the naiad without risking the kids. But it was too late for them to help. It was up to you now.

All those powerful muscles you'd just been admiring responded, uncoiling from Cas' torso and shoulders. You launched yourself from him in time for Dean and Sam to see you become visible again as you lost contact, and swear creatively.

You traveled in a perfect arc away from them. Up, out, down, and then you were surrounded by a cloud of bubbles.

You were in the lake.

Although it had looked cold and dark and frightening from the car, now that you were _in_ it, this lake seemed…nice. You could see for a _long_ ways, and your webbed fingers, so clumsy above the water, made it easy to use your arms to adjust your position now.

You swallowed a gulp of water by accident, but felt it passing over a brand new set of organs in your throat and then out behind your ears. Gills! You could breathe underwater!

The lake was full of underwater rock formations, rising up towards you like misshapen fingers. And it was deep. It looked to be close to eighty feet near the bottom. There _had_ to be some kind of magic going on to keep this place so secluded. A lake like this should be every freshwater diver's vacation spot.

 _Kill the naiad first_ , you scolded yourself. _Admire the pretty lake later._

You looked around, quickly spotting the naiad fleeing, and hearing cries for help coming from the two girls she was dragging along behind her.

Trying not to think too hard about what she had been doing to those girls, you tore after them.

Or rather, you tried to. It took you a moment to get the hang of how to move. It wasn't just tail-flicking. And if you moved your tail too dramatically, your whole body suddenly changed direction. Experimentally, you moved your head to one side, then the other, trying to mimic the motions you'd seen watching Shark Week with Dean. The undulating movement slid down your body naturally, almost without your conscious direction and you shot forwards in the water, a little faster than you were prepared for.

 _Now_ you tore after the naiad.

The water of the lake, which had felt warm at the surface, grew chillier as you dived downwards. And most of the colors filtered out, leaving everything shaded in blue and darker blue. And despite it being mid-afternoon on the surface, it was twilight down here. You had lost a lot of ground (so to speak) figuring out how to swim. Now that you were here, on the bottom of the lake, you'd lost sight of your prey.

You pulled up your harpoon gun, desperately searching for some way to find a trail, and then realized you were being an idiot. You closed your eyes for a moment and _listened_.

Sound doesn't translate very well from water to air. Or vice versa, really. Someone shouting above the surface is usually pretty inaudible to a swimmer. But, for all of that, sound travels very well through the water. Better than it does through the air, in fact.

You heard the witch's voice hiss, “Be quiet!” and a frightened child crying. To your left.

You wasted no time now. You easily weaved your way through the water, your powerful tail propelling you along at a fantastic speed, dodging around those massive rock spires reaching upwards. And you made your way straight towards…

Another house. Apparently the witch had another place to live down here. There were no doors, just huge open archways on multiple floors, so you barreled straight in, hoping you'd get there so fast she wouldn't have time to prepare a defense.

She hadn't. But you weren't prepared either. Because in the house you found not two, but at least fifteen girls, ranging in age from around six to about twenty.

You leveled your harpoon at the witch's face. “What kind of sick monster are you?” You ground out, your voice sounding odd and distorted under water.

“I have to draw power from somewhere,” the witch replied. She lifted her hand and made a grasping motion towards your heart.

Then she recoiled in horror. “Why can't I draw power from you?”

“Hex bag made by an angel, bitch,” you snapped back. “You magicked the wrong hunter.” And with that you pulled the trigger.

At this distance, even underwater, you weren't going to miss. Your harpoon caught the naiad right between the eyes, skewering all the way through her head. She was dead even before the force of the shot shoved her backwards.

The naiad's spells were instantly broken. Which left you and about fifteen girls suddenly changed back into humans. Only you were still eighty feet under water. And you were suddenly unable to breathe. Plus being back in the same clothes you'd been wearing when you were first magicked.

You snatched the littlest girl within grabbing distance, watching as everyone else able to did the same, and then you all pushed off for the surface, rocketing upwards.

…For about fifteen feet. But the friction of the water on you slowed you all down.

You started kicking for the light that seemed so far above you, desperately striking for it with your legs. But it didn't seem to get any closer, and then it actually started getting darker. You tried to kick as hard as you could, but your attempts seemed to get more and more feeble.

Just before the light vanished entirely, you thought you felt hands take you by the arms.

The darkness was comfortable. Maybe you'd stay here for a while. Except no. Something had you rushing upwards again, or feeling like you were. Honestly, maybe you should open your eyes just to figure out what was going on?

You woke up coughing, feeling like half the lake was pouring out of your lungs. Castiel's hand was warm on your face, Sam was holding your hands in both of his, and your head was laying in Dean's lap. The girls from the lake were watching in a semi-circle, all with terrified looks that were now bleeding into relief as you coughed and barfed up lake water.

But you managed to raise your head a bit to see the happiness on the faces of Sam, Dean, and Cas before sinking back to Dean's knees and saying, “I'm so glad I'm not a mermaid anymore.”

Apparently, you had the two eldest girls to thank for rescuing you. Although they were naturally just as human as you were, they'd spent a _lot_ longer as mermaids. They were great at swimming and holding their breath. It was they who had hauled you up from the blue-black waters, and straight to Cas' healing hands.

Sam called the police from the ex-naiad's landline. The four of you hid by the Impala as the girls were picked up by confused but elated officers, telling the story the story Dean had coached them on, about a crazy lady who'd kidnapped them to force them to build her house. Which, while incomplete, was actually mostly true. Aside from using them as magical batteries, the witch _had_ forced the girls to do construction on her houses, above and below the lake. All of the girls claimed not to know where this woman had gone, though they all described her accurately. She was dead, so it wouldn't really matter if the police looked for her. Even if the police actually made any arrests, it would be easy enough for one of the girls to identify that person as innocent.

Apparently all but three of them had families to go back to. On the whole, not a bad hunt.

By the time the police, social workers, firefighters, and EMTs all cleared off, it was beyond late. Nobody wanted to let Cas drive, and the human contingent of your team was all too exhausted to be safe on the road. So Dean, Sam, and you crawled into the back seat of the Impala, sleeping in a sort of puppy pile while Cas sat on top of the car and kept watch.

You easily made it back to the bunker the next day, happily grabbing your gear and striding for the door. But before you could enter, Sam grabbed your arm.

“So, please tell me you learned something from this little adventure?” he said.

“You should not be wearing anything you're fond of when you are transfigured?” you offered, knowing full well what he was getting at. But also, you were _really_ gonna miss that harpoon gun, which had been absorbed when you changed back to a human.

Now Sam, Dean, _and_ Cas were all giving you a ferocious glare.

“Wait for back-up,” you sighed.

Sam nodded in satisfaction.

“Good,” Dean said. “Now. Time for some pie, and some _Deep Blue Sea_.”

You glared at him, but said, “Make it _The Hunt For Red October_ , and you're on.”

Cas smiled. “I think I'd like to watch that film, instead of just knowing about it.”

Sam rolled his eyes, but he had popcorn popped and was already setting up the projector screen by the time everyone else had finished dropping off their gear in their rooms.

So you dragged out big cushions, or flopped on the top of tables, or just generally made yourselves comfy, and let the comforting sounds of a Russian chorus wash over you as the film began.

It was good to be home.

END

**Author's Note:**

> Hooray! I've been stuck in a writing rut for so long.
> 
> Mermaids are most commonly associated with sirens, mythologically. But since the show's already done sirens (and it was the weirdest thing ever seeing Hoyt Fortenberry bro-flirting with Dean), I figured I'd have to go a different route.
> 
>  _Nymphs And Their Ways_ is the title of a book on Mr. Tumnus' shelf in C.S. Lewis' _The Lion, The Witch, And The Wardrobe_. _Dreadful Denizens Of The Deep_ is the title of a book Harry, Ron, and Hermione read while researching for the second task in _Harry Potter and the Goblet Of Fire_.
> 
> The _Swan Lake_ book to which our protagonist refers is an actual book. _Swan Lake_ as told by Margot Fonteyn and illustrated by Trina Schart Hyman. The book is out-of-print, but if you find a copy, I recommend hanging on to it. The art is fantastic.
> 
> The diving stuff (water getting colder, colors going blue, sound behavior underwater, etc.) is all drawn from my experience as a SCUBA diver. Granted, I've never been freshwater diving, but I'm gonna just go with it.
> 
> The thing of it is, it's hard to make lungs and gills play nicely together in the same body. Gills work by drawing oxygen out of the water and absorbing it straight into the bloodstream. If you breathe with gills, lungs become big empty sacks of space that could be squeezed or burst by water pressure, which is actually really, really bad. A SCUBA diver compensates for the pressure changes by constantly breathing (equalizing their lungs), and equalizing their sinuses (like you would try to “pop” your ears when traveling up a mountain). Which means having gills underwater makes lungs not only redundant, but actively dangerous. I have dealt with this issue by ignoring it completely and pretending it doesn't exist.


End file.
